水文变异条件下的水库生态调度模型

发布时间：2018-09-04 12:23

【摘要】：水资源在人类生产和生活中扮演着重要角色,但自然状态的水资源并不能完全与人类的需求相适应,为了对水资源进行更加合理的时空分配,控制水流,减少洪涝灾害的发生,达到兴利除害的目的,水利工程被大量修建,不可否认,水利工程的建设缓解了社会日趋增加的能源需求,有效减少了水害的发生,但其所带来的生态问题也越发凸显。水库作为最具代表性的水利工程,其生态问题在近几年成为了研究的热点,水库的修建改变了河流原有的运动形态,阻碍了河流的连通性,使相应的水文指标发生了较大变化如水文特征、理化性质、河流形态以及沿岸生态等,为了降低水库对下游生态系统的影响,本文针对水库生态问题,考虑水文变异的影响,以尼尔基水库为例,建立了水文变异条件下的水库生态调度模型,主要研究内容为:(1)结合水文变异诊断系统,将人类扰动作为变异的主要诱因,通过初步诊断、详细诊断及综合诊断,确定所选时间序列的水文变异节点,以此将水文时间序列划分为三类:天然状态下的水文序列,用以推求天然状态下的生态流量;弱人类干扰下的水文序列,用以推求次天然状态下的生态流量;强人类干扰下的水文序列,用以推求现状生态流量。(2)选择水文指标法求解生态流量,并以逐月频率计算法为基础,缩小时间尺度,其中冰封期(11月-次年3月)以月为时间尺度,非冰封期(4月-10月)以旬为时间尺度,求解得出天然状态、次天然状态、现状条件下的最大、适宜、最小生态流量,并以不考虑水文变异条件下的生态流量作为对照组,将得到的结果用Tennant法进行评价。(3)以发电量最大为目标,水量平衡、水位、水轮机最大过机流量、水电站出力、水电站出力特性、生态流量为约束条件,FA算法为求解方法,建立了常规的水库生态调度模型和非充分生态约束条件下的生态调度模型。(4)以四种状态下的最小及适宜生态流量作为水库下泄流量的下阈值,最大生态流量作为水库下泄流量的上阈值,进行五种典型水文年的水库常规生态调度,分析考虑水文变异后的调度结果与原调度原则、不考虑生态变异的调度结果之间的差异性。(5)针对部分调度结果满足最小生态流量约束而不满足适宜生态流量约束的情况,提出了以最小生态流量约束的调度结果为基础,逐步向适宜生态流量约束靠近的非充分生态约束流量求解方法,并以最小生态约束流量为下限,非充分生态约束流量为上限,通过引入松弛变量λ建立发电量与生态保证程度的关系,采用Kmin法与Kmax-1法并结合Tennant评价,确定了非充分生态约束条件下水库生态调度的最佳平衡点。结果表明,在现有调度规则下,河流原有的生态系统得不到有效保护,对于来水较多的年份弃水较多,水资源得不到有效利用;水文变异条件下的生态调度,可以在水量不足的年份提供较低生态保证程度的调度方案,减轻对河流系统的破坏程度;水库经济效益与生态效益之间存在矛盾,在枯水期较为明显,在丰水期可以得到有效缓解;不宜直接选取最小生态流量约束下的调度结果作为调度方案;非充分生态约束条件下的生态调度模型可以有效解决部分调度模型存在调度结果满足最小生态流量约束而不满足适宜生态流量约束的问题,在六种生态约束条件下的生态保证程度分别可提高60%、80%、40%、60%、70%、70%,相应的电量损失率仅为2.01%、1.13%、1.28%、1.47%、2.16%、2.08%。
[Abstract]:Water resources play an important role in human production and life, but the natural state of water resources can not fully meet the needs of human beings. In order to make a more reasonable space-time distribution of water resources, control the flow of water, reduce the occurrence of floods and waterlogging disasters, to achieve the purpose of promoting benefits and eliminating harm, a large number of water conservancy projects have been built. The construction of the reservoir has alleviated the increasing energy demand of the society and effectively reduced the occurrence of water hazards, but the ecological problems brought about by the reservoir have become more and more prominent. In order to reduce the impact of the reservoir on the downstream ecosystem, this paper considers the impact of hydrological variation on the reservoir ecology, and takes Nierji Reservoir as an example to establish the reservoir ecological regulation under the condition of hydrological variation. The main research contents of the degree model are as follows: (1) Combining with the hydrological variation diagnostic system, human disturbance is taken as the main inducement of variation, and the hydrological variation nodes of the selected time series are determined through preliminary diagnosis, detailed diagnosis and comprehensive diagnosis. The hydrological time series can be divided into three types: the hydrological sequence in the natural state to deduce the natural state. (2) Choose the hydrological index method to calculate the ecological discharge, and reduce the time scale based on the monthly frequency calculation method, in which the ice cover period (November-March) is the ice cover period. Taking monthly as the time scale and ten days as the time scale in non-freezing period (April-October), the natural state, sub-natural state, the maximum, suitable and minimum ecological flow under the current conditions were obtained. The ecological flow without considering the hydrological variability was taken as the control group, and the results were evaluated by Tennant method. (3) The maximum power generation was taken as the objective. Standard, water balance, water level, maximum turbine flow, output of hydropower station, output characteristics of hydropower station and ecological flow are constraints, and FA algorithm is used to solve the problem. A conventional reservoir ecological operation model and an ecological operation model under the condition of inadequate ecological constraints are established. (4) Minimum and appropriate ecological flow under four conditions are taken as water. Under the lower threshold of reservoir discharge, the maximum ecological discharge is used as the upper threshold of reservoir discharge. The routine ecological operation of reservoir in five typical hydrological years is carried out. The dispatching results after considering hydrological variation and the original dispatching principle are analyzed, and the difference between the dispatching results without considering ecological variation is not considered. (5) Some dispatching results satisfy the minimum ecology. In the case of flow constraints which do not satisfy the appropriate ecological flow constraints, a method for solving the incomplete ecological flow constraints is proposed, which is based on the scheduling results of the minimum ecological flow constraints and approaches the appropriate ecological flow constraints step by step. Quantity lambda establishes the relationship between power generation and ecological assurance degree, and uses Kmin method, Kmax-1 method and Tennant evaluation to determine the optimal balance point of reservoir ecological operation under the condition of insufficient ecological constraints. Under the condition of hydrological variability, the ecological regulation can provide a lower ecological guarantee degree of operation plan in the year of insufficient water, and reduce the damage degree to the river system. It is inappropriate to directly select the scheduling results under the constraints of minimum ecological flow as the scheduling scheme; the ecological scheduling model under the conditions of inadequate ecological constraints can effectively solve the problem of partial scheduling model with the scheduling results satisfying the constraints of minimum ecological flow and not satisfying the constraints of appropriate ecological flow, and the ecological scheduling model under six ecological constraints. The guarantee degree can be increased by 60%, 80%, 40%, 60%, 70%, respectively. The corresponding loss rate of electricity is only 2.01%, 1.13%, 1.28%, 1.47%, 2.16%, 2.08%.
【学位授予单位】：东北农业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TV697.1

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